Artificial Selection and Genetic Engineering

Selective Breeding Choosing the BEST traits for breeding. Most domesticated animals are products of selective breeding. Also known as: Artificial Selection Techniques used in selective breeding: 1. Hybridization 2. Inbreeding

HORSES

Hybridization Crossing different individuals to bring together the best traits of both organisms Produces hybrids Hybrids can be different species crossed together or different types (variety) within the same species.

Golden Doodle and Puggle

Can you think of other fruit or vegetable hybrids?

Inbreeding Humans have inbred several domesticated animals and plants to develop “breeds” and “varieties.” Researchers use inbred strains to assure genetic similarities in their experiments. Inbreeding may also increases the chance of negative recessive traits showing up. Golden retrievers - epilepsy Dalmations - hereditary deafness

Increasing Variation Breeders can increase variation in a population by inducing mutations Mutation = any change in DNA Mutations can happen randomly, as in this Scottish fold cat. Cat with a mutation for the ears. A new strain of Oil-eating bacteria was produced.

Mutations can produce new kinds of plants Ex: Plants can sustain multiple sets of chromosomes - Polyploidy.

Manipulating DNA Making any changes in the DNA code is: Genetic Engineering How DNA is Manipulated: Extract DNA from cells Cut DNA into smaller pieces (Restriction enzymes) Identify the sequence of bases in a DNA molecule (Gel electrophoresis) Make unlimited copies of DNA Combining different strands of DNA (recombinant DNA)

Transgenic Organisms Definition: Organisms that contain genes from another organism. Transgenic microorganisms – bacteria that produce human insulin. Transgenic plants – major part of agriculture; weed resistance; insecticides Transgenic animals – growth hormones in livestock, resistance to bacterial infections, production of human proteins.

Transgenic animals Gene causes these mice to glow in the dark. Normally, the gene is found in jellyfish.

Transgenic plants: GM crops!

Putting bacteria to work for us. Recombinant DNA The human Insulin gene is inserted into the bacterial DNA. The bacteria now produces human insulin at a much faster pace and cheaper than animals can.

Cloning Natural clones – identical twins DNA must be identical to be a clone. Lifespan usually shortened. Health problems multiplied. Chance of survival before birth low Dolly the sheep cloned, 1 st mammal

A donor cell is taken from a sheep’s udder. Donor Nucleus These two cells are fused using an electric shock. Fused Cell The fused cell begins dividing normally. Embryo The embryo is placed in the uterus of a foster mother. Foster Mother The embryo develops normally into a lamb—Dolly Cloned Lamb Egg Cell An egg cell is taken from an adult female sheep. The nucleus of the egg cell is removed. Section 13-4 Figure Cloning of the First Mammal

Summary questions Page 221, number: 1-2 Page 222, number: 8 – 10 Use complete sentence to answer the questions